Pulsation reducer

Aug. 1, 1967

D. W. BIRDWELL

3,333,604

PULSATION REDUCER

Filed July 28, 1964

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INVENTOR. £&gt;£i&lt;//£ £/. &amp;//&amp;£&gt; £&amp;£££,

BY

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United States Patent Office

3,333,604

Patented Aug. 1, 1967

3,333,604

PULSATION REDUCER

Dewie W. Birdwell, 1917 Coleman Ave., Snyder, Tex. 79549

Filed July 28, 1964, Ser. No. 385,652 2 Claims. (CI. 138—30)

This invention relates to a pulsation reducer for pumpactuated fluid systems.

While the invention is primarily devised for use in such high pressure fluid systems as car washer apparatus, wherein the pumps employed are usually of the high speed dual piston type, the invention is also applicable to other systems, employing other types of pumps, including rotary pumps.

In present car washer apparatus, employing high speed dual piston pumps, producing in the range of 3450 strokes per minute, and a correspondingly similar number of pulses or surges, at pressures in the range of 400-500 p.s.i., the accompanying vibration and noise is destructive and troublesome to customers. In fact, the vibration produced not only makes difficult the handling of the washer hoses in car washing operations, but substantially reduces their useful life, requiring frequent and expensive replacements. Further, the vibrations accompanying the operation of such car washers requires special and expensive installation, including the burying, in concrete, of the pipes leading to the hoses, and the more massive and expensive construction of the buildings, housing the car --------, .....- — &lt;x_{UU luc} uecK are a rorem, washers, which would otherwise be literally destroyed by 30 belLshaped connector 70 has a reduced diameter i _ The primary object of the present invention is the provision of a pulsation reducer, which, when incorporated m hydraulic systems of the kind indicated above, re- ----------- — „_{ωι1υπ ιύ Dears} duces and substantially eliminates the destructive vibra- 35 outer end of the neck 68. At its outer end the tions mentioned, so that quiet and non-destructive opera- &gt;

tion is obtained, together with long life for the hoses, and the resultant substantial reductions of operating expenses including longer life for the system components, espepiolltr tlla ι-m—-. — -,. , ....... .

ing the systems, at less cost, are made feasible.

Another object of the invention is the provision of a device of the character indicated above, which is simple and inexpensive in construction, is easy to service, when of the head 18. The valve body 34 has treaded therein a valve seat 40, through which works an outwardly extending valve stem 41, on whose intermediate part is a valve of the head 18. The valve body 34 has threaded therein a the inner end of the seat 40, in sealing relation to the passage through the seat, by a coil spring 44, which is compressed between the valve head 42 and a member 46 whieh bears against a stop 48, at the inner end of the bore 50 of the body 34. The valve 36 is provided for convenient introduction of and release of air under pressure into the housing 16, through the head 18, in order to pro^V1/, ^a P^neurnatic cushion, as hereinafter explained.

The housing head 20 is formed, at its center, with a relatively large diameter circular axial opening 52 which is aligned with the valve body 34. An annular shoulder 54 is provided, at the inner edge of the opening 52, whose inner surface 56 is flush with a flattened central inner surface 58 of the head 20.

. A removable perforated, heavy gauge disc 60 is seated m the opening 52, has a reduced diameter inner end portion 62, which fits in the opening of the shoulder 54, and has a flat inner surface 64, which is flush with the inner surface 58 of the head 20. The disc 60 is formed therethrough with a plurality of uniformly distributed bores 66, of relatively small diameter.

An external axial, internally threaded neck 68 surrounds the opening 52. The neck 68 can be in the form of a pipe collar welded to the head 20, or be formed integral therewith, when the head and the neck are a forging A ηΡ.ΙΙ-ΛηαΠΑΓΪ οπητ,αηΐ/.» ΓΤΛ 1___ . i ... ° ° /V uas a reaucea diameter inner portion 72 which threads into the neck 68, and has an inner end 73 bearing against the disc 60 and holding the disc against the annular shoulder 54. A shoulder 74 at the outer end of the threaded portion 72 bears against’the outer end of the neck 68. At its outer end, the connector . has an axial, reduced diameter terminal 76, into which is adapted to be threaded, as indicated at 78, a high pressure output pipe or line 12, leading from a pump (not . , - - - — ~ vcut- · snownj. At least one lateral pipe or line 14 is rnnnRrtAri cially the pumps; and lighter constructed buildings, hous- ^{40 to the} pipe 12, and leads to the point of utilization such mg the systems. ?it less rn?t arx moru as a hose of a car washer (not shown) '

A circular diaphragm 84, normally substantially of the same diameter as the housing heads 18 and 20 has a peripheral portion 86, clamped between the flanges 22 of necessary, and whose installation is quick and easy, and 45 ^the heads, the traversed by the bolts 26 In equilibrium is readily done by an unskilled mechanic. the diaphragm, as shown in phantom lines, in FIGUURE

... . . 2, is equidistant from the central areas of the Ser sS faces of the heads 18 and 20, so as to severally define _n, // ^ar//^e heads 18 and 20, an air pressure , ~ ----- -- —1 a hydraulic or water pressure chamber 90.

The diaphragm 84 is resilient and stretchable or elastic and is preferably made of corded rubber or the equivalent, so that the diaphragm is capable of being moved and , . --------------J or against the head

20, as shown in full lines in FIGURE 3, according to an existing imbalance of pressures in the chambers 88 and

In operation, the system involved being in operation, ⁶⁰ ο» · ¹ “^{e hydrauIic or} water pressure in the chamber 90 is at a maximum, air pressure is applied to the valve 36, in order to produce a pneumatic cushion within the chamber 88, sufficient to counterbalance the hydraulic j - . - —------“ xr—--, pressure within the chamber 90 to the extent ™τ·™»· “s and accompanying vibration. While a pressure gauge (not shown) can be used in conjunction with the valve 36 and another pressure gauge (not shown) used in conjunction with the hydraulic pressure line 12, for setting t r- nonoeooz,, ...p_neUmatlC Chamber 88, in practice this desired condition can be more easily and quickly obtained, simply by applying the available air

FIGURE 1 is an end view of a device of the present invention;

1GUKE 2 is a schematic side elevation thereof, show- 50 ^or pneumatic cushion chamber 88 and mg the device installed in a high pressure hydraulic pump system;

FIGURE 3 is an enlarged longitudinal section taken on the line 3—3 of FIGURE 1; and

FIGURE 4 is a fragmentary transverse section taken 55 stretched to lie against the head 18 on the line 4—4 of FIGURE 3. —

Referring in detail to the drawings, the illustrated device 10 is shown connected to the output line 12 of a high speed pump actuated hydraulic system, the line 12 having a lateral branch 14, to which is connected utilization means, such as a car washer hose (not shown).

The device 10 comprises a circular, relatively flat housing 16, composed of two opposed, substantially simi^^ai?,^^ads and 20, each having peripheral flanges 22, equally circumferentially spaced intervals, extend through the flanges 22 and secure the heads together.

The head 18 is formed, at its center, with a flat external surface 28 which is engaged by a sealing washer 30 pnomcf a — + 1___ rm — — -- * the tubular body 34, of a Shrader type valve 36, which is threaded in an axial bore 38, formed through the center

3,333,604 «&gt; pressure through the valve 36, until the noise and vibration, otherwise present in the system, is reduced to the desired degree. Where the device is to be installed at a location lacking an adequate source of air under pressure, the chamber 88 may be pre-pressurized, before the device is brought to the site of its installation.

An adequate pneumatic cushion having been obtained in the pneumatic chamber 88, by the injection of air pressure thereinto, as above explained, usually half the median pressure in the hydraulic chamber 90, the dia- phragm 84 is in equilibrium. However, whenever a transient pulsation of hydraulic fluid takes place in the hydraulic pressure line 12, at a higher than medium pressure, a pulsation is produced in the chamber 90, which exceeds the median pressure, the diaphragm 84 is displaced toward the head 18, whereby the pneumatic cushion in the chamber 88 is compressed and absorbs the pulsation. As the pulsation subsides, the diaphragm 84 return toward its neutral or median position, and, where subsiding of the pulse produces a momentary drop below median pressure, in the hydraulic pressure line 12, the diaphragm can pass its median position, and bear against the head 20, as shown in FIGUURE 3.

In continuous operation, however, and due to the high speed and frequency of pulsations present in a hydraulic system driven by a high speed, high pressure dual piston pump, the pressure and counter pressures on the diaphragm 84, produced by the pulsations and the reset action of the pneumatic cushion, in the chamber 88, the diaphragm flutters to either side of its median position, with sufficient speed and force to reduce or eliminate the high speed pulsations, and hence, the destructive and noisy vibration of the system, which would otherwise be present.